Two Republicans backed by most party regulars fended off vigorous primary challenges in Northern Virginia yesterday to win congressional nominations against incumbent Democrats they have previously confronted.

The landslide victories of former 8th District Rep. Stanford E. Parris and lawyer Frank R. Wolf in the 10th District showed that mainstream party activists will control the suburban Virginia Republican organization firmly in the November elections.

Parris easily defeated former state legislator Robert L. Thorburn, an ultraconservative church school administrator who had the support of several far-right and fundamentalist groups. In unofficial voting results from an extremely light turnout at the polls, the margin was a lopsided three-to-two for Parris.

In November, Parris will face Democratic Rep. Herbert E. Harris II, who knocked him out of Congress in 1974 after one term.

In the 10th District, Wolf rolled over state Del. Martin H. Perper and Falls Church Mayor Harold L. Miller, receiving a whopping 74.6 percent of the vote compared to 17.7 for Perper and a scant 7.7 percent for Miller.

He now faces Democratic Rep. Joseph L. Fisher, the incumbent he challenged unsuccessfully two years ago.

Parris trounced Thoburn decisively in the 8th District's more populous areas, racking up a plurality of 1,481 votes in Alexandria and 1,975 in southern Fairfax County. Thoburn managed to edge Parris by slight margins in Manassas Park, northern Stafford County and Prince William County.

Perper and Miller failed to overtake Wolf in any of the 10th District's jurisdictions, which include northern Fairfax County, Fairfax City, Falls Church, Loudoun County and Arlington.

Neither primary victor wasted time yesterday in attacking his old nemesis.

"Joe Fisher is close to the Carter administration," Wolf proclaimed from his victory party at a Tysons Corner hotel. "It's very difficult to live in this congressional district and say you don't like what the Carter administration is doing, and yet still vote for Joe Fisher for your congressman."

Republicans in Northern Virginia and elsewhere already are predicting GOP election sweeps this November warning that Carter and his congressional supporters won't survive the president's economic and foreign policy debacles.

"We've seen the ultraconservative, and we're going to see the ultraliberal -- the other end of the spectrum -- in the general election," said Parris, 50, who geared up his primary campaign in the last days amid reports that conservative Christian voters were stampeding to Thoburn. "I have always suggested that I was middle America, the middle of the spectrum," Parris argued.

Counter-attacking, Harris kicked off his own campaign last night with allegations that Parris had improperly handled his responsibilities as a congressman. He accused Parris of taking more than $3,000 from an office stationery account that should have been refunded to the U.S. Treasury, and he challenged his GOP foe to debate on this and other issues.

Parris called the charge unfounded, saying the funds he withdrew from his congressional office account was money he had paid in on other occassions.

Discussing his primary loss, Thoburn said "untruths in the media" had contributed to his defeat. He said labels like "right wing," "ultraconservative" and "fundamentalist" distorted his political views.

"What do you mean right wing?" he asked. "If they're going to call me right wing, why are'nt they going to call the opposition side left wing? Why don't they refer to Herb Harris or Stan Parris as left wing?"

This was Thoburn's fourth election defeat, including three unsuccessful congressional primary races in the 8th District and the recent loss of his General Assembly seat.

Yesterday's defeat, he sad, "will make me more determined than ever to organize for the principles we believe in, including the free enterprise system, a strong national defense and the family."

State Del. James R. Dillard (R-Fairfax), a member of Parris's campaign committee, claimed his candidate's primary win was a victory for the mainstream of the GOP. "I think it's an indication that the majority of Republican voters prefer a moderate conservative position, as opposed to a far-right, extreme position," he said.

Perper congratulated Wolf and said his determined campaigning "had reaped the harvest of years of hard work."

It was Wolf's close race against Rep. Fisher two years ago that won him the respect of a broad spectrum of party activists and most GOP officials and put them squarely in the Wolf camp this time around.

Wolf, a 41-year-old Arlington attorney spent an estimated $80,000 to shore up his support when it appeared Perper's aggressive campaigning was having an impact.

Perper, a state delegate from Fairfax serving his second term in the legislature, apealed to moderate and liberal voters of both parties to back him in the primary. He particularly made an issue of the conservative Wolf's opposition to ratification of of the Equal Rights Amendment and his call for federal prohibition of abortion except to save the life of the mother. c

These appeals apparently fell on deaf ears. There was little evidence yesterday of cross-over voting, and even Republicans who said they disagreed with Wolf on some issues supported him against Perper and Miller. Primary Results (TABLE) *3*8th Congressional District (COLUMN)Parris(COLUMN)Thorburn Fairfax(COLUMN)5940(COLUMN)3965 Alexandria(COLUMN)2337(COLUMN)856 Pr. William(COLUMN)1113(COLUMN)1288 Manassas(COLUMN)192(COLUMN)167 Manassas Park(COLUMN)74(COLUMN)80 Stafford Co.(COLUMN)36(COLUMN)49 Total(COLUMN)9692(60.2%)(COLUMN)6405(39.8%)(END TABLE) (TABLE) *4*10th Congressional District (COLUMN)Wolf(COLUMN)Miller(COLUMN)Perper Fairfax Co.(COLUMN)8202(COLUMN)703(COLUMN)2047 Fairfax City(COLUMN)516(COLUMN)25(COLUMN)119 Falls Church(COLUMN)492(COLUMN)215(COLUMN)76 Loudoun County(COLUMN)1024(COLUMN)75(COLUMN)233 Arlington(COLUMN)3430(COLUMN)393(COLUMN)776 Total(COLUMN)13664(COLUMN)1411(COLUMN)3251 (COLUMN)(74.6%)(COLUMN)(7.7%)(COLUMN)(17.7%)(END TABLE)